@article{ref1,
title="Average Error and Constant Error in Air Traffic System Design",
journal="Journal of engineering psychology",
year="1963",
author="Pfeiffer, MG",
volume="2",
number="2",
pages="68-81",
abstract="[Abstract unavailable]  <p>Language: en</p>",
language="en",
issn="0022-085X",
doi="",
url="http://dx.doi.org/"
}